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Zeng D, Chen C, Huang Z, Gu J, Zhang Z, Cai T, Peng J, Huang W, Dang Z, Yang C. Influence of macromolecules and electrolytes on heteroaggregation kinetics of polystyrene nanoplastics and goethite nanoparticles in aquatic environments. JOURNAL OF HAZARDOUS MATERIALS 2024; 477:135257. [PMID: 39047557 DOI: 10.1016/j.jhazmat.2024.135257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 07/14/2024] [Accepted: 07/17/2024] [Indexed: 07/27/2024]
Abstract
Fate and transport of nanoplastics in aquatic environments are affected by their heteroaggregation with minerals in the presence of macromolecules. This study investigated the heteroaggregation of polystyrene nanoplastics (PSNPs) with goethite nanoparticles (GNPs) under the influence of macromolecules [humic acid (HA), bovine serum albumin (BSA), and DNA] and electrolytes. Under 1 mg C/L macromolecule, raising electrolyte concentration promoted heteroaggregation via charge screening, except that calcium bridging with HA also enhanced heteroaggregation at CaCl2 concentration above 5 mM. At all NaCl concentrations and CaCl2 concentration below 5 mM, 1 mg C/L macromolecules strongly retarded heteroaggregation, ranking BSA > DNA > HA. Raising macromolecule concentration strengthened such stabilization effect of all macromolecules in NaCl solution and that of DNA and BSA in CaCl2 solution by enhancing steric hindrance. However, 0.1 mg C/L BSA slightly promoted heteroaggregation in CaCl2 solution due to stronger electrostatic attraction than steric hindrance. In CaCl2 solution, raising HA concentration strengthened its destabilization effect via calcium bridging. Macromolecules having more compact globular structure and higher molecular weight may exert greater steric hindrance to inhibit heteroaggregation more effectively. This study provides new insights on the effects of macromolecules and electrolytes on heteroaggregation between nanoplastics and iron minerals in aquatic environments.
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Affiliation(s)
- Dehua Zeng
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Chengyu Chen
- College of Natural Resources and Environment, Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, South China Agricultural University, Guangzhou 510642, China
| | - Ziqing Huang
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Jingyi Gu
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Zhiyu Zhang
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Tingting Cai
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Jiamin Peng
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Weilin Huang
- Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Zhi Dang
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China
| | - Chen Yang
- College of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China.
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Liang A, Liu C, Branicio PS. Colloid Transport in Bicontinuous Nanoporous Media. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:10868-10883. [PMID: 38756103 PMCID: PMC11140755 DOI: 10.1021/acs.langmuir.4c00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/18/2024]
Abstract
Colloid transport and retention in porous media are critical processes influencing various Earth science applications, from groundwater remediation to enhanced oil recovery. These phenomena become particularly complex in the confined spaces of nanoporous media, where strong boundary layer effects and nanoconfinement significantly alter colloid behavior. In this work, we use particle dynamics models to simulate colloid transport and retention processes in bicontinuous nanoporous (BNP) media under pressure gradients. By utilizing particle-based models, we track the movement of each colloid and elucidate the underlying colloid retention mechanisms. Under unfavorable attachment conditions, the results reveal two colloid retention mechanisms: physical straining and trapping in low-flow zone. Furthermore, we investigate the effects of critical factors including colloid volume fraction, d, pressure difference, ΔP, interaction between colloids and BNP media, Ec-p, and among colloids, Ec-c, on colloid transport. Analysis of breakthrough curves and colloid displacements demonstrates that higher values of d, lower values of ΔP, and strong Ec-p attractions significantly increase colloid retention, which further lead to colloid clogging and jamming. In contrast, Ec-c has minimal impact on colloid transport due to the limited colloid-colloid interaction in nanoporous channels. This work provides critical insights into the fundamental factors governing colloid transport and retention within stochastic nanoporous materials.
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Affiliation(s)
- Aoyan Liang
- Mork Family Department of Chemical
Engineering and Materials Science, University
of Southern California, Los Angeles, California 90089-0242, United States
| | - Chang Liu
- Mork Family Department of Chemical
Engineering and Materials Science, University
of Southern California, Los Angeles, California 90089-0242, United States
| | - Paulo S. Branicio
- Mork Family Department of Chemical
Engineering and Materials Science, University
of Southern California, Los Angeles, California 90089-0242, United States
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Zhao K, Shang J. Transport of biochar colloids under unsaturated flow condition: Roles of chemical aging and cation type. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160415. [PMID: 36427725 DOI: 10.1016/j.scitotenv.2022.160415] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 11/03/2022] [Accepted: 11/18/2022] [Indexed: 06/16/2023]
Abstract
Biochar colloids released from biochar materials are ubiquitous in the environment and undergo environmental transformation processes that may alter their properties. Natural subsurface environments are usually under unsaturated conditions, which could affect the transport of biochar colloids. This study investigated the transport of pristine and aged biochar colloids under unsaturated conditions by aggregation test, bubble column experiment, and sand column experiment. After aging, the biochar showed a more negative, hydrophilic, and rougher surface. Compared with pristine biochar colloids, aged biochar colloids in NaCl solution were not retained at the air-water interface (AWI) due to their more hydrophilic and rougher surface. In CaCl2 solution, more pristine and aged biochar colloids were retained at the AWI because Ca2+ weakened the electrostatic repulsion between biochar colloids and the AWI. With the decrease in saturation, the transport of pristine and aged biochar colloids decreased by 17 %‑67 % through the retention at AWI and air-water-solid (AWS) interface. The transport of biochar colloids in NaCl solution was increased by 10 %‑20 % after aging as the aged biochar was not retained at the AWI. The difference of transport between pristine and aged biochar colloids in CaCl2 solution (<8 %) was lower than that in NaCl solution due to the enhanced retention of aggregated biochar colloids at the AWI and AWS interfaces. These results highlight the importance of the surface structure of biochar on its behavior in the environment, which is essential for assessing the potential of biochar application for carbon sequestration and environmental protection.
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Affiliation(s)
- Kang Zhao
- College of Land Science and Technology, China Agricultural University, Key Laboratory of Arable Land Conservation in North China, Beijing 100193, PR China
| | - Jianying Shang
- College of Land Science and Technology, China Agricultural University, Key Laboratory of Arable Land Conservation in North China, Beijing 100193, PR China.
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4
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Physiological characteristics, geochemical properties and hydrological variables influencing pathogen migration in subsurface system: What we know or not? GEOSCIENCE FRONTIERS 2022; 13. [PMID: 37521131 PMCID: PMC8730742 DOI: 10.1016/j.gsf.2021.101346] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The global outbreak of coronavirus infectious disease-2019 (COVID-19) draws attentions in the transport and spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in aerosols, wastewater, surface water and solid wastes. As pathogens eventually enter the subsurface system, e.g., soils in the vadose zone and groundwater in the aquifers, they might survive for a prolonged period of time owing to the uniqueness of subsurface environment. In addition, pathogens can transport in groundwater and contaminate surrounding drinking water sources, possessing long-term and concealed risks to human society. This work critically reviews the influential factors of pathogen migration, unravelling the impacts of pathogenic characteristics, vadose zone physiochemical properties and hydrological variables on the migration of typical pathogens in subsurface system. An assessment algorithm and two rating/weighting schemes are proposed to evaluate the migration abilities and risks of pathogens in subsurface environment. As there is still no evidence about the presence and distribution of SARS-CoV-2 in the vadose zones and aquifers, this study also discusses the migration potential and behavior of SARS-CoV-2 viruses in subsurface environment, offering prospective clues and suggestions for its potential risks in drinking water and effective prevention and control from hydrogeological points of view.
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Liu X, Liang Y, Peng Y, Meng T, Xu L, Dong P. Sensitivity of the Transport of Plastic Nanoparticles to Typical Phosphates Associated with Ionic Strength and Solution pH. Int J Mol Sci 2022; 23:ijms23179860. [PMID: 36077260 PMCID: PMC9455956 DOI: 10.3390/ijms23179860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/17/2022] Open
Abstract
The influence of phosphates on the transport of plastic particles in porous media is environmentally relevant due to their ubiquitous coexistence in the subsurface environment. This study investigated the transport of plastic nanoparticles (PNPs) via column experiments, paired with Derjaguin–Landau–Verwey–Overbeek calculations and numerical simulations. The trends of PNP transport vary with increasing concentrations of NaH2PO4 and Na2HPO4 due to the coupled effects of increased electrostatic repulsion, the competition for retention sites, and the compression of the double layer. Higher pH tends to increase PNP transport due to the enhanced deprotonation of surfaces. The release of retained PNPs under reduced IS and increased pH is limited because most of the PNPs were irreversibly captured in deep primary minima. The presence of physicochemical heterogeneities on solid surfaces can reduce PNP transport and increase the sensitivity of the transport to IS. Furthermore, variations in the hydrogen bonding when the two phosphates act as proton donors will result in different influences on PNP transport at the same IS. This study highlights the sensitivity of PNP transport to phosphates associated with the solution chemistries (e.g., IS and pH) and is helpful for better understanding the fate of PNPs and other colloidal contaminants in the subsurface environment.
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Liang Y, Luo Y, Shen C, Bradford SA. Micro- and nanoplastics retention in porous media exhibits different dependence on grain surface roughness and clay coating with particle size. WATER RESEARCH 2022; 221:118717. [PMID: 35749921 DOI: 10.1016/j.watres.2022.118717] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 05/31/2022] [Accepted: 06/05/2022] [Indexed: 06/15/2023]
Abstract
The presence and/or coating of natural colloids (e.g., clays and metal oxides or hydroxides) on collector surfaces has frequently been demonstrated to enhance the retention of engineered colloids that are negatively charged due to favorable electrostatic interactions. However, this work demonstrates that the presence of natural clay coating can lead to reduced or nonmonotonic retention of micro- and nanoplastics (MNPs). Column experiments were carried out to systematically investigate the transport of MNPs with different sizes in relatively smooth and rough sands that had various clay coating fractions. These coating fractions on the collector were found to significantly influence MNP retention in a complex manner that changed with the colloid size and the roughness properties of the sand. This observation was attributed to the impact of clay coatings on the roughness and morphology properties of collector surfaces that were dominant over surface charge. Scanning electron microscopy and interaction energy calculations on surfaces with pillars or valleys indicate that mechanisms that contributed to MNP retention changed with the colloid size. In particular, retention of nanosized plastics was mainly controlled by interactions on convex/concave locations that changed with the solution chemistry, whereas microsized plastics were also strongly influenced by the applied hydrodynamic torque and straining processes. Additionally, the significant sensitivity of MNP retention under a low-level ionic strength also reflects the importance of roughness and charge heterogeneities. These observations are important for investigating the mechanisms of colloid transport in natural systems that ubiquitously exhibit clay coating on their surfaces.
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Affiliation(s)
- Yan Liang
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
| | - Yonglu Luo
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Chongyang Shen
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Scott A Bradford
- Sustainable Agricultural Water Systems Unit, USDA, ARS, Davis, CA 95616, United States
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Shen C, Teng J, Zheng W, Liu D, Ma K. Significant Mobility of Novel Heteroaggregates of Montmorillonite Microparticles with Nanoscale Zerovalent Irons in Saturated Porous Media. TOXICS 2022; 10:toxics10060332. [PMID: 35736940 PMCID: PMC9227587 DOI: 10.3390/toxics10060332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/08/2022] [Accepted: 06/11/2022] [Indexed: 12/04/2022]
Abstract
This study conducted laboratory column experiments to systematically examine the transport of novel heteroaggregates of montmorillonite (Mt) microparticles with nanoscale zerovalent irons (nZVIs) in saturated sand at solution ionic strengths (ISs) ranging from 0.001 to 0.2 M. Spherical nZVIs were synthesized using the liquid phase reduction method and were attached on the plate-shaped Mt surfaces in monolayer. While complete deposition occurred for nZVIs in sand, significant transport was observed for Mt-nZVI heteroaggregates at IS ≤ 0.01 M despite the transport decrease with an increasing loading concentration of nZVIs on Mt. The increased mobility of Mt-nZVI heteroaggregates was because the attractions between nZVIs and sand collectors were reduced by the electrostatic repulsions between the Mt and the collector surfaces, which led to a decreased deposition in the sand columns. Complete deposition occurred for the Mt-nZVI heteroaggregates at IS ≥ 0.1 M due to a favorable deposition at Derjaguin–Landau–Verwey–Overbeek (DLVO) primary energy minima. Interestingly, a large fraction of the deposited heteroaggregates was released by reducing IS because of a monotonic decrease of interaction energy with separation distance for the heteroaggregates at low ISs (resulting in repulsive forces), in contrast to the irreversible deposition of nZVIs. Therefore, the fabricated heteroaggregates could also have high mobility in subsurfaces with saline pore water through continuous capture and release using multiple injections of water with low ISs. Our study was the first to examine the transport of heteroaggregates of a plate-like particle with spherical nanoparticles in porous media; the results have important implications in the use of nanoscale zerovalent iron for in situ soil and groundwater remediation.
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Affiliation(s)
- Chongyang Shen
- Key Laboratory of Degraded and Unused Land Consolidation Engineering, Ministry of Natural Resources of the People’s Republic of China, Xi’an 710075, China
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China; (J.T.); (D.L.); (K.M.)
- Correspondence: ; Tel.: +86-1062732959
| | - Jinan Teng
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China; (J.T.); (D.L.); (K.M.)
| | - Wenjuan Zheng
- Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
| | - Dong Liu
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China; (J.T.); (D.L.); (K.M.)
| | - Ke Ma
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China; (J.T.); (D.L.); (K.M.)
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8
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Pourakaberian A, Mahani H, Niasar V. Dynamics of electrostatic interaction and electrodiffusion in a charged thin film with nanoscale physicochemical heterogeneity: implications for low-salinity waterflooding. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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9
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Yang Y, Yuan W, Hou J, You Z. Review on physical and chemical factors affecting fines migration in porous media. WATER RESEARCH 2022; 214:118172. [PMID: 35196620 DOI: 10.1016/j.watres.2022.118172] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/01/2022] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Permeability reduction and formation damage in porous media caused by fines (defined as unconfined solid particles present in the pore spaces) migration is one of the major reasons for productivity decline. It is well accepted that particle detachment occurs under imbalanced torques arising from hydrodynamic and adhesive forces exerted on attached particles. This paper reviewed current understanding on primary factors influencing fines migration as well as mathematical formulations for quantification. We also introduced salinity-related experimental observations that contradict theoretical predictions based on torque balance criteria, such as delayed particle release and attachment-detachment hysteresis. The delay of particle release during low-salinity water injection was successfully explained and formulated by the Nernst-Planck diffusion of ions in a narrow contact area. In addition to the widely recognized explanation by surface heterogeneity and the presence of low-velocity regions, we proposed a hypothesis that accounts for the shifting of equilibrium positions, providing new insight into the interpretation of elusive attachment-detachment hysteresis both physically and mathematically. The review was finalized by discussing the quantification of anomalous salinity effect on adhesion force at low- and high-salinity conditions.
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Affiliation(s)
- Yulong Yang
- State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102200, China.
| | - Weifeng Yuan
- State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102200, China
| | - Jirui Hou
- State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102200, China
| | - Zhenjiang You
- Center for Sustainable Energy and Resources, Edith Cowan University, Joondalup, WA 6027, Australia; School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia; Centre for Natural Gas, The University of Queensland, Brisbane, QLD 4072, Australia.
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Li T, Shen C, Johnson WP, Ma H, Jin C, Zhang C, Chu X, Ma K, Xing B. Important Role of Concave Surfaces in Deposition of Colloids under Favorable Conditions as Revealed by Microscale Visualization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4121-4131. [PMID: 35312300 DOI: 10.1021/acs.est.1c07305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This study conducted saturated column experiments to systematically investigate deposition of 1 μm positively charged polystyrene latex micro-colloids (representing microplastic particles) on negatively charged rough sand, glass beads, and soil with pore water velocities (PWV) from 4.9 × 10-5 to 8.8 × 10-4 m/s. A critical value of PWV was found below which colloidal attachment efficiency (AE) increased with increasing PWV. The increase in AE with PWV was attributed to enhanced delivery of the colloids and subsequent attachment at concave locations of rough collector surfaces. The AE decreased with further increasing PWV beyond the threshold because the convex sites became unavailable for colloid attachment. By simulating the rough surfaces using the Weierstrass-Mandelbrot equation, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) interaction energy calculations and torque analysis revealed that the adhesive torques could be reduced to be comparable or smaller than hydrodynamic torques even under the favorable conditions. Interestingly, scanning electron microscopic experiments showed that blocking occurred at convex sites at all ionic strengths (ISs) (e.g., even when the colloid-colloid interaction was attractive), whereas at concave sites, blocking and ripening (i.e., attached colloids favor subsequent attachment) occurred at low and high ISs, respectively. To our knowledge, our work was the first to show coexistence of blocking and ripening at high ISs due to variation of the collector surface morphology.
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Affiliation(s)
- Tiantian Li
- School of Environmental Engineering, Henan University of Technology, Zhengzhou, Henan 450001, China
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Chongyang Shen
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - William P Johnson
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, United States
| | - Huilian Ma
- Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, United States
| | - Chao Jin
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510006, China
| | - Chenxi Zhang
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Xianxian Chu
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Ke Ma
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
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Xu Z, Pan D, Tang Q, Wei X, Liu C, Li X, Chen X, Wu W. Co-transport and co-release of Eu(III) with bentonite colloids in saturated porous sand columns: Controlling factors and governing mechanisms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 298:118842. [PMID: 35031401 DOI: 10.1016/j.envpol.2022.118842] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/21/2021] [Accepted: 01/09/2022] [Indexed: 06/14/2023]
Abstract
Accurate prediction of the colloid-driven transport of radionuclides in porous media is critical for the long-term safety assessment of radioactive waste disposal repository. However, the co-transport and corelease process of radionuclides with colloids have not been well documented, the intrinsic mechanisms for colloids-driven retention/transport of radionuclides are still pending for further discussion. Thus the controlling factors and governing mechanisms of co-transport and co-release behavior of Eu(III) with bentonite colloids (BC) were discussed and quantified by combining laboratory-scale column experiments, colloid filtration theory and advection dispersion equation model. The results showed that the role of colloids in facilitating or retarding the Eu(III) transport in porous media varied with cations concentration, pH, and humic acid (HA). The transport of Eu(III) was facilitated by the dispersed colloids under the low ionic strength and high pH conditions, while was impeded by the aggregated colloids cluster. The enhancement of Eu(III) transport was not monotonically risen with the increase of colloids concentration, the most optimized colloids concentration in facilitating Eu(III) transport was approximately 150 mg L-1. HA showed significant promotion on both Eu(III) and colloid transport because of not only its strong Eu(III) complexion ability but also the increased dispersion of HA-coated colloid particles. The HA and BC displayed a synergistic effect on Eu(III) transport, the co-transport occurred by forming the ternary BC-HA-Eu(III) hybrid. The transport patterns could be simulated well with a two-site model that used the advection dispersion equation by reflecting the blocking effect. The retarded Eu(III) on the stationary phase was released and remobilized by the introduction of colloids, or by a transient reduction in cation concentration. The findings are essential for predicting the geological fate and the migration risk of radionuclides in the repository environment.
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Affiliation(s)
- Zhen Xu
- Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou, 730000, China; School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Duoqiang Pan
- Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou, 730000, China; School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China.
| | - Qingfeng Tang
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Xiaoyan Wei
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Chunli Liu
- Beijing National Laboratory for Molecular Sciences, Fundamental Science Laboratory on Radiochemistry and Radiation Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Xiaolong Li
- China Academy of Engineering Physics, Mianyang, 621000, China
| | - Ximeng Chen
- Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou, 730000, China; School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Wangsuo Wu
- Frontiers Science Center for Rare Isotopes, Lanzhou University, Lanzhou, 730000, China; School of Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000, China
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12
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Novel analytical expressions for determining van der Waals interaction between a particle and air-water interface: Unexpected stronger van der Waals force than capillary force. J Colloid Interface Sci 2021; 610:982-993. [PMID: 34876261 DOI: 10.1016/j.jcis.2021.11.157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/18/2021] [Accepted: 11/24/2021] [Indexed: 01/05/2023]
Abstract
HYPOTHESIS Analytical expressions for calculating Hamaker constant (HC) and van der Waals (VDW) energy/force for interaction of a particle with a solid water interface has been reported for over eighty years. This work further developed novel analytical expressions and numerical approaches for determining HC and VDW interaction energy/force for the particle approaching and penetrating air-water interface (AWI), respectively. METHODS The expressions of HC and VDW interaction energy/force before penetrating were developed through analysis of the variation in free energy of the interaction system with bringing the particle from infinity to the vicinity of the AWI. The surface element integration (SEI) technique was modified to calculate VDW energy/force after penetrating. FINDINGS We explain why repulsive VDW energy exists inhibiting the particle from approaching the AWI. We found very significant VDW repulsion for a particle at a concave AWI after penetration, which can even exceed the capillary force and cause strong retention in water films on a solid surface and at air-water-solid interface line. The methods and findings of this work are critical to quantification and understanding of a variety of engineered processes such as particle manipulation (e.g., bubble flotation, Pickering emulsion, and particle laden interfaces).
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13
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14
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Liang Y, Luo Y, Lu Z, Klumpp E, Shen C, Bradford SA. Evidence on enhanced transport and release of silver nanoparticles by colloids in soil due to modification of grain surface morphology and co-transport. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:116661. [PMID: 33592438 DOI: 10.1016/j.envpol.2021.116661] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/30/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Natural soils have frequently been considered to decrease the mobility of engineered nanoparticles (NPs) in comparison to quartz sand due to the presence of colloids that provide additional retention sites. In contrast, this study demonstrates that the transport and release of silver nanoparticles (AgNPs) in sandy clay loam and loamy sand soils were enhanced in the presence of soil colloids that altered soil grain surface roughness. In particular, we found that the retention of AgNPs in purified soils (colloid-free and acid-treated) was more pronounced than in raw (untreated) soils or soils treated to remove organic matter (H2O2 or 600 °C treated). Chemical analysis and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy demonstrated that the grain surfaces of raw and organic matter-removed soils were abundant with metal oxides and colloids compared to purified soil. Column transport and release experimental results, SEM images, and interaction energy calculations revealed that a significant amount of concave locations on purified soils hindered AgNP release by diffusion or ionic strength (IS) reduction due to deep primary energy minima. Conversely, AgNPs that were retained in soils in the presence of soil colloids were more susceptible to release under IS reduction because the primary minimum was shallow on the tops of convex locations created by attached soil colloids. Additionally, a considerable fraction of retained AgNPs in raw soil was released after cation exchange followed by IS reduction, while no release occurred for purified soil under the same conditions. The AgNP release was highly associated with soil colloids and co-transport of AgNPs and soil colloids was observed. Our work is the first to show that the presence of soil colloids can inhibit deposition and facilitate the release and co-transport of NPs in soil by alteration of the soil grain surface morphology and shallow primary minimum interactions.
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Affiliation(s)
- Yan Liang
- School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China.
| | - Yonglu Luo
- School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China
| | - Zhiwei Lu
- School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China
| | - Erwin Klumpp
- Agrosphere Institute, IBG-3, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Chongyang Shen
- Department of Soil and Water Sciences, China Agricultural University, Beijing, 100193, China
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15
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Wu T, Yang Z, Hu R, Chen YF, Zhong H, Yang L, Jin W. Film entrainment and microplastic particles retention during gas invasion in suspension-filled microchannels. WATER RESEARCH 2021; 194:116919. [PMID: 33609906 DOI: 10.1016/j.watres.2021.116919] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/20/2021] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Understanding of microplastics transport mechanism is highly important for soil contamination and remediation. The transport behaviors of microplastics in soils are complex and influenced by various factors including soil and particle properties, hydrodynamic conditions, and biota activities. Via a microfluidic experiments we study liquid film entrainment and microplastics transport and retention during two-phase displacement in microchannels with one end connected to the air and the other connected to the liquid with suspended particles. We discover three transport patterns of microplastic particles, ranging from no deposition to particle entrapment and to particle layering within liquid films, depending on the suspension withdrawal rates and the particle volume fraction in the suspension. The general behavior of particle motion is effectively captured by the film thickness evolution which is shown to be dependent on a modified capillary number Ca0 taking into account the effects of flow velocity, particle volume fraction, and channel shape. We also provide a theoretical prediction of the critical capillary number Ca0* for particle entrapment, consistent with the experimental results. In addition, the probability of microplastics being dragged into the trailing liquid film near the gas invading front is found to be proportional to both particle volume fraction and the capillary number. This work elucidates the microplastics transport mechanism during unsaturated flow, and therefore is of theoretical and practical importance to understand the contaminant migration in many natural and engineered systems spanning from groundwater sources to water treatment facilities.
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Affiliation(s)
- Ting Wu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, PR China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, PR China
| | - Zhibing Yang
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, PR China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, PR China.
| | - Ran Hu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, PR China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, PR China
| | - Yi-Feng Chen
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, PR China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan 430072, PR China
| | - Hua Zhong
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, PR China
| | - Lei Yang
- School of Civil and Environmental Engineering, Harbin Institute of Technology, Shenzhen (HITSZ), Shenzhen 518055, PR China.
| | - Wenbiao Jin
- School of Civil and Environmental Engineering, Harbin Institute of Technology, Shenzhen (HITSZ), Shenzhen 518055, PR China
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16
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Bradford SA, Sasidharan S, Kim H, Gomez-Flores A, Li T, Shen C. Colloid Interaction Energies for Surfaces with Steric Effects and Incompressible and/or Compressible Roughness. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1501-1510. [PMID: 33470105 DOI: 10.1021/acs.langmuir.0c03029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Colloid aggregation and retention in the presence of macromolecular coatings (e.g., adsorbed polymers, surfactants, proteins, biological exudates, and humic materials) have previously been correlated with electric double layer interactions or repulsive steric interactions, but the underlying causes are not fully resolved. An interaction energy model that accounts for double layer, van der Waals, Born, and steric interactions as well as nanoscale roughness and charge heterogeneity on both surfaces was extended, and theoretical calculations were conducted to address this gap in knowledge. Macromolecular coatings may produce steric interactions in the model, but non-uniform or incomplete surface coverage may also create compressible nanoscale roughness with a charge that is different from the underlying surface. Model results reveal that compressible nanoscale roughness reduces the energy barrier height and the magnitude of the primary minimum at separation distances exterior to the adsorbed organic layer. The depth of the primary minimum initially alters (e.g., increases or decreases) at separation distances smaller than the adsorbed organic coating because of a decrease in the compressible roughness height and an increase in the roughness fraction. However, further decreases in the separation distance create strong steric repulsion that dominates the interaction energy profile and limits the colloid approach distance. Consequently, adsorbed organic coatings on colloids can create shallow primary minimum interactions adjacent to organic coatings that can explain enhanced stability and limited amounts of aggregation and retention that have commonly been observed. The approach outlined in this manuscript provides an improved tool that can be used to design adsorbed organic coatings for specific colloid applications or interpret experimental observations.
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Affiliation(s)
| | - Salini Sasidharan
- USDA, ARS, SAWS Unit, Davis, California 95616, United States
- Environmental Sciences Department, University of California, Riverside, California 92521, United States
| | - Hyunjung Kim
- Department of Mineral Resources and Energy Engineering, Jeonbuk National University, 664-14 Deokjin, Jeonju, Jeonbuk 54896, Republic of Korea
| | - Allan Gomez-Flores
- Department of Mineral Resources and Energy Engineering, Jeonbuk National University, 664-14 Deokjin, Jeonju, Jeonbuk 54896, Republic of Korea
| | - Tiantian Li
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
| | - Chongyang Shen
- Department of Soil and Water Sciences, China Agricultural University, Beijing 100193, China
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